Portal de Periódicos da CAPES

Quality of life, should we bother?

2003; Wiley; Volume: 58; Issue: 4 Linguagem: Inglês

10.1034/j.1398-9995.2003.00108.x

1398-9995

Roy Gerth van Wijk,

Olfactory and Sensory Function Studies

During the last three decades the focus on quality of life (QoL) has been increased both in clinical research and practice. It was not until the early 1990s, that health-related quality of life (HRQL) questionnaires in the field of rhinitis and asthma were introduced (1–3). Since then, assessment of QoL has come to stay in allergy research. The awareness that the QoL of patients is an important issue to be managed has penetrated into consensus reports. For instance, the International Consensus Report on the diagnosis and management of rhinitis describes severity of seasonal allergic rhinitis in terms of occasional symptoms, prominent nasal or prominent eye symptoms (4). Seven years later rhinitis severity has been based on the impact of disease on daily life in the recently published ARIA guidelines (5). In moderate or severe disease patients may encounter sleep disorders. Normal daily functioning in school, work and leisure may be impaired and symptoms may be troublesome. The difference between the two consensus reports illustrates the notion that attention for the burden of disease is important in the management of allergic disorders. From a clinical point of view the focus on HRQL is understandable. In the office patients do not report symptoms, they report the effect of symptoms on their daily life and their perception of well-being. The burden of disease, as the patient perceives it, forms the basic motivation to seek medical aid or to undergo therapy. Adherence to therapy requires changes in health, perceived by patients as relevant and outweighing eventual disadvantages of intervention. From a research point of view the need to assess HRQL might be less obvious. Although nowadays the inclusion of QoL questionnaires in clinical trials is almost a matter of course, on the face of it just another outcome measure seems to be added. In most clinical trials the outcome of QoL questionnaires corresponds very well with the results of other more clinical outcome measures. Therefore, the question has to be addressed whether these instruments are not redundant. A few strong arguments to assess QoL can be put forward. First, in general, HRQL is moderately associated with the classical outcome measures such as lung function, symptom scores and nasal tests (6–8). This moderate association has been considered as an indication that QoL instruments measure other components of health than do classical tests. In line with this, in some studies the results of the various outcome measures do not correspond with each other. In a recent study comparing intranasal budesonide and fluticasone it was found that both drugs were equally effective in suppressing symptoms, whereas budesonide did have a better effect on general QoL (9). This might indicate that patients perceive differences, not captured by conventional symptom scores. Recently, Juniper showed a greater improvement in asthma-specific QoL in a group of patients who switched from a conventional chlorofluorocarbon (CFC), beclomethason dipropionate (BDP), to hydrofluroalkane-134a (HFA) BDP extrafine aerosol at half the daily dose, while clinical indexes of pulmonary function and asthma control were similar in the HFA-BDP vs CFC-BDP group (8). The reversed situation i.e. significant effects on classical outcomes (symptom scores, medication use, peak flow or FEV1) without important change in two generic and two specific HRQL measures has been described in a study to the effect of formoterol – a long-acting β2-agonist – in mild to moderate asthmatic patients (10). The authors suggested that the latter discrepancies reflect a limited performance of HRQL measures in mild asthmatic patients. Alternatively, it is possible that the minor changes in symptom scores and lung function caused by the intervention are not perceived by patients as clinical relevant. A second argument to use these instruments is that the outcome can be interpreted more easily in terms of clinical significance. The issue of ‘What is a clinical relevant change?’ is less well solved with respect to symptom scores, visual analogue scale and medication scores. Lung function tests may not be interpreted easily as patients with the same level of pulmonary function may differ tremendously in daily functioning. By construction and design QoL instruments comprise issues that are considered by patients as important. For several instruments attempts have been made to express clinical relevance into magnitude of changes. For instance, a 0.5 change on a 7-point scale (used in the McMaster asthma and rhinitis questionnaires) has been put forward as a minimal important difference (11). Research into the properties of QoL instruments underpins the scientific base of these outcome measures. In this issue Baiardini et al. introduce a new QoL questionnaire, designed for patients with rhinitis and asthma (12). Before accepting such an instrument in clinical research a thorough validation process has to be completed. The paper of Baiardini presents the steps of validation (i.e. criterion validity, construct validity, test–retest and internal reliability and responsiveness). In general, symptom- or medication scores, visual analogue scales and diary cards – well accepted instruments in clinical trials – do not have such a methodological foundation. Research into the impact of allergic rhinitis or asthma ignores the fact that patients with allergy are often characterized by the presence of several disorders. Rates of allergic rhinitis among asthmatics vary from 28 to 50% in studies published in the 1970s and 1980s (13–15). Recently, in a population-based study the prevalence of rhinitis in patients with asthma was estimated at 78% (16). Edfors-Lubs showed that the prevalence of rhinitis in patients with dermatitis was 29% (13). In a recent study in patients with a house dust mite allergy it was shown that – based on history and clinical symptoms – 92% of the asthmatic patients and 85% of the patients with atopic dermatitis could be diagnosed as having rhinitis (17). Inclusion of a positive nasal provocation to house dust mites did not result in a substantial lower prevalence of rhinitis. The classical approach to estimate impairment in QoL across the borders of disease comprises the use of generic QoL questionnaires. With the generic SF36 it has been shown that in a mixed population of patients with rhinitis and asthma, patients reveal impaired QoL in general, whereas the presence of asthma or asthma symptoms further deteriorates QoL (16, 18). However, these generic instruments are not only less tailored to the problems of the patients compared with disease-specific questionnaires, but their performance in terms of responsiveness is also less (19). It is the merit of the study of Baiardini et al. (12) that they introduce an instrument – Rhinasthma – designed for patients who may have both rhinitis and asthma, thereby acknowledging the fact that patients with asthma may be bothered by nasal problems and vice versa. In a way this outcome measure meets the concept of rhinitis and asthma as ‘one airway – one disease’. Another important aspect of the Rhinasthma questionnaire is that the instrument may replace two other questionnaires, thereby meeting the need for simple and effective tools. Thus, in the last 10–15 years evaluation of QoL has come to stay in the field of allergy with good reason. Now we are shifting our attention to the refining of instruments. The next step could be that we not only simply use those instruments in clinical trails, but also find ways to implement them in the process of understanding and managing our patients in daily care.